Visible‐NIR Photodetectors Based on Low‐Dimensional GeSe Micro‐Crystals: Designed Morphology and Improved Photoresponsivity

Abstract

Abstract GeSe micro‐sheets and micro‐belts have been synthesized by a facile one‐pot wet chemical method in 1‐octadecene solvent and oleic acid solvent, respectively. The adsorption of more oleic acid molecules on the (002) plane promoted growth along [010] direction of the GeSe micro‐belts and limited carrier transport in this direction, resulting in higher carrier concentration and mobility of the GeSe micro‐belts. The performance of the photodetectors based on the single GeSe micro‐sheet and the single GeSe micro‐belt was investigated under illumination at 532 nm, 980 nm and 1319 nm. Both, photodetectors based on a single GeSe micro‐sheet and a single GeSe micro‐belt, exhibit a high photoresponse, short response/recovery times, and long‐term durability. Moreover, the photodetector based on a single GeSe micro‐belt displays a broadband response with a high responsivity (5562 A/W at 532 nm, 1546 A/W at 980 nm) and detectivity (3.01×10 12 Jones at 532 nm, 8.38×10 11 Jones at 980 nm). These excellent characteristics render single GeSe micro‐belts very interesting for use as highly efficient photodetectors, especially in the NIR region.